Tossing official mail from the Social Security Administration into the recycling bin can cost you thousands of dollars in lost benefits, unexpected tax penalties, or missed appeal deadlines. While much of the mail you receive feels like routine paperwork, specific federal notices serve as legal proof of income, vital tax documents, or strict time-sensitive warnings. If you throw away the wrong letter, you risk forfeiting your right to challenge costly benefit reductions or failing to correct inaccuracies in your lifetime earnings record. Knowing which documents to file safely away—and how long to keep them—protects your financial independence and guarantees you receive every dollar you earned throughout your career.